Total Phenolic Content and in vitro Antiproliferative Activity of Tragia brevipes (Pax) and Tetradenia riparia (Hochst) Leaves Extract

Tragia brevipes and Tetradenia riparia have been widely used in traditional medicine. T. brevipes relief stomach pain and in treatment of rheumatism while T. riparia; heal chest pains, stomach-ache, malaria and act as antioxidant. However, scanty data exist on their potential anticancer activity. The total phenolic content was determined and anti-proliferative activity of the Methanol-Dichloromethane extract from the leaves evaluated against cancerous cell lines. The total phenolic content of the plants extract was determined using an UV visual spectrophotometer at 765 nm. The 3- (4-5-dimethyl-2-thiazoly)-2, 5-diphenyltetrazolium bromide (MTT) cell proliferation bioassay was used to test for anti-proliferative activity on Hela (cervical), DU145 (prostrate) and HCC (breast) cancer cell lines and Vero (normal) cell. T. brevipes and T. riparia had a phenolic concentration of 30.44 and 20.25 µg/ml, respectively. Both plants showed anti-proliferative activity on cancer cells with the most inhibited being DU145 with an IC50 of 29.67 ± 4.60 µg/ml for T. brevipes and 11.45 ± 0.87 µg/ml for T. riparia. The standard 5 Fluorouracil had an IC50 of 5.04 ± 4.12 µg/ml on DU145. T. riparia had the highest antiproliferative activity of 65.54 ± 16.85 µg/ml on Hela cells and 62.84 ± 1.10 µg/ml on HCC. T. brevipes had an IC50 of 661.11 ± 15. 12 µg/ml on Hela cells and 703.09 ± 18.35 µg/ml on HCC. Extracts from both plants were highly selective on DU145 cancer cells with a selectivity index (SI) of 21.62 for T. brevipes and 7.88 for T. riparia. Methanol-Dichloromethane extracts from T. brevipes and T. riparia exert anti-proliferative activity, however, the active compound (s) and the mechanisms of anti-proliferative action need to be investigated further.